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Subchapter 7. General Industry Safety Orders
Group 10. Gas Systems for Welding and Cutting
Article 86. Manifolding of Cylinders to Headers for Shop Pipe Line Supply Systems and Pressure Reducing Regulators and Hose

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§4836. Oxygen Manifolds.

(a) Oxygen manifolds shall not be located in an acetylene generator room. Oxygen manifolds shall be separated from fuel-gas cylinders or combustible materials (especially oil or grease), a minimum distance of 20 feet or by a noncombustible barrier at least 5 feet high having a fire resistance rating of at least one-half hour.

(b) An oxygen manifold, to which cylinders having an aggregate capacity of more than 6,000 cubic feet of oxygen are connected, shall be located outdoors or in a separate noncombustible building. Such a manifold if located inside a building having other occupancy, shall be located in a separate room of noncombustible construction.

(c) Manifolds shall be of substantial construction suitable for use with oxygen at a pressure of 250 p.s.i.g. They shall have a minimum bursting pressure of 1,000 p.s.i.g. and shall be protected by a safety relief device which will relieve at a maximum pressure of 500 p.s.i.g. DOT-4L200 cylinders have safety devices which relieve at a maximum pressure of 250 p.s.i.g. (or 235 p.s.i.g. if vacuum insulation is used).

(1) Hose and hose connections subject to cylinder pressure shall comply with Section 4839.

(2) Hose shall have a minimum bursting pressure of 1,000 p.s.i.g.

(3) The assembled manifold including leads shall be tested and proven gas-tight at a pressure of 300 p.s.i.g. The fluid used for testing oxygen manifolds shall be oil free and noncombustible.

(4) The following sign shall be conspicuously posted at each manifold:

Low-Pressure Manifold

Do Not Connect High-Pressure Cylinders

Maximum Pressure--250 P.S.I.G.

(d) Portable outlet headers shall not be used indoors except for temporary service where the conditions preclude a direct supply from outlets located on the service piping system.

(1) Each outlet on the service piping from which oxygen or fuel-gas is withdrawn to supply a portable outlet header shall be equipped with a readily accessible shutoff valve.

(2) Hose and hose connections used for connecting the portable outlet header to the service piping shall comply with Section 4839.

(3) Master shutoff valves for both oxygen and fuel-gas shall be provided at the entry end of the portable outlet header.

(4) Each service outlet on portable outlet headers shall be provided with a valve assembly that includes a detachable outlet seal cap, chained or otherwise attached to the body of the valve.

(5) Materials and fabrication procedures for portable outlet headers shall comply with Sections 4822, 4823 and 4824.

(6) Portable outlet headers shall be provided with frames which will support the equipment securely in the correct operating position and protect them from damage during handling and operation.

NOTE: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.


1. New subsections (c) and (d) filed 5-16-75; effective thirtieth day thereafter (Register 75, No. 20).

2. Amendment of subsections (a), (b) and (c)(3) filed 6-12-87; operative 7-12-87 (Register 87, No. 26).

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